Using a Volt meter to determine batter level? How to wire it properly accuracy?

[MH Hawker]

Re: Using a Volt meter to determine batter level? How to wire it properly accuracy?

I also only use one battery to keep down weight and have done this for a long time. You can use a volt meter but I find it a lot simpler to use a percent of charge meter because of the very small amount of volt drop involved. I have used several of these but the only one that works like it is should and thier simple to wire in.

http://www.tjtrailers.com/store/goldeneye-two-battery-energy-gauges.html


this is a common voltage chart. The drop is .52 volts to 50 % state of charge and why a volt meter isnt the best way to go.

 

[Silvertip]

Re: Using a Volt meter to determine batter level? How to wire it properly accuracy?

A % of charge meter is nothing more than a voltmeter calibrated in % rather than volts. If the voltmeter reades 12 volts or less under load, the battery needs charging. Until that point -- it is ok to go.

 

[MH Hawker]

Re: Using a Volt meter to determine batter level? How to wire it properly accuracy?

Yes but the scaling is easer to read.

 

[Silvertip]

Re: Using a Volt meter to determine batter level? How to wire it properly accuracy?

OOF-DA. I don't feel the number 12 is that hard to distinguish on a voltmeter. Since most voltmeters have a scale that reads 8 - 18 volts, when the needle is just above the number "8" it would be a pretty good indication the battery is 0% charged. No biggy though -- use what you like.

 

[scbasschaser]

Re: Using a Volt meter to determine batter level? How to wire it properly accuracy?

I also only use one battery to keep down weight and have done this for a long time. You can use a volt meter but I find it a lot simpler to use a percent of charge meter because of the very small amount of volt drop involved. I have used several of these but the only one that works like it is should and thier simple to wire in.

http://www.tjtrailers.com/store/goldeneye-two-battery-energy-gauges.html


this is a common voltage chart. The drop is .52 volts to 50 % state of charge and why a volt meter isnt the best way to go.


View attachment 128712

mH,
I had look at this very meter and wanted to get a simple easy to read but had a hard time finding one that i use a circular cut out. Ended up with the 8-18 dial type and seems there is still some discussion on what empty will be, below 12 or just above 8 but I can at least see my charge unit working and if Im above 12 with just a depth finder and trolling i`ll be in good shape. Thanks for the tip. Pretty large hole you have to cut for that panel btw.

 

[M9.9]

Re: Using a Volt meter to determine batter level? How to wire it properly accuracy?

Here'a list of batt voltage v. discharge percentages. Seems to me auto chargers are using voltage assessment to complete charging and if that's true I don't see why an accurate dc v meter cannot be used to determine the level of charge in a battery:

Voltage State of Charge
12.6+ 100%
12.5 90%
12.42 80%
12.32 70%
12.20 60%
12.06 50%
11.9 40%
11.75 30%
11.58 20%
11.31 10%
10.5 0%

 

[MH Hawker]

Re: Using a Volt meter to determine batter level? How to wire it properly accuracy?

I had look at this very meter and wanted to get a simple easy to read but had a hard time finding one that i use a circular cut out. Ended up with the 8-18 dial type and seems there is still some discussion on what empty will be, below 12 or just above 8 but I can at least see my charge unit working and if Im above 12 with just a depth finder and trolling i`ll be in good shape. Thanks for the tip. Pretty large hole you have to cut for that panel btw.

I is my understanding that 100 % to 50 % is the normal range of use on a deep cycle and that when you go below that it can shorten the life and why it is good to keep a close eye on it.

I don't see why an accurate dc v meter cannot be used to determine the level of charge in a battery:

It sure can and a lot do use just that, a % meter is a volt meter with a diffrent face and scale but it has a lot more needle movment with minual voltage drops and is easer to see and you dont have to keep track of what drop means how much is left.

 

[azboater2]

Re: Using a Volt meter to determine batter level? How to wire it properly accuracy?

Here'a list of batt voltage v. discharge percentages. Seems to me auto chargers are using voltage assessment to complete charging and if that's true I don't see why an accurate dc v meter cannot be used to determine the level of charge in a battery:

Voltage State of Charge
12.6+ 100%
12.5 90%
12.42 80%
12.32 70%
12.20 60%
12.06 50%
11.9 40%
11.75 30%
11.58 20%
11.31 10%
10.5 0%

Yea, I agree that 10.5 volts no load on a battery is gonna be pretty darn dead. With a charging system (did we find out if he in fact has a charging system?), I just turn on the key and look at the volt meter, it should be setting on 12V, then start the engine and it should be at least 1/2 volt above no load to show it's charging under most conditions, usually it about 14v. Above 14.5 V MAY indicate a overcharge condition.